1. Field of the Invention
The invention relates to the field of soil mechanics where measurement of soil percent compaction and moisture content are required for road beds and construction foundations. More particularly, the invention relates to the measurement of soil electrical resistance and soil electrical capacitance at a radio frequency, wherein electrodes are used to connect the measurement instrumentation to the soil.
2. Prior Art
There have been many applications wherein soil electrical properties have been measured to determine geological characteristics of soils and earth structures in situ. Generally the electrode structure has not been identified in the description of these inventions. U.S. Pat. No. 5,450,012, issued to Champagne, et. al. on Sep. 12, 1995, describes a Soil Electrode design that is claimed to be useful for determination the resistance of a volume of soil. Other prior art includes U.S. Pat. No. 2,611,643 of R. V. Higgins, granted on Sep. 23, 1952 that describes an automatic sprinkling device which includes two electrodes inserted into soil. U.S. Pat. No. 3,905,551 of Charles Ayme de la Lachevreliere, granted on Sep. 17, 1975 describes a soil sprinkling device employing two electrodes, one lying in the upper sprinkled layer, and the other lying within the permanently moist layer at sufficient depth.